Objective: To describe the presenting characteristics, hospital course, and hospital charges associated with hospital admissions for head trauma in young children at a regional pediatric trauma center, and to examine whether these factors differ among abused and non-abused subjects. Method: Comparative case series study involving a retrospective medical record review of children less than 3 years of age admitted to Children's Hospital of Pittsburgh from January 1, 1995 to December 31, 1999. Subjects (n = 377) were identified on the basis of ICD-9-CM codes for head injury. Subjects were classified as abused or non-abused based on standard criteria using information about the type of injuries, the history provided by the caretaker, and physical and radiographic findings. Results: Eighty nine (23.6%) subjects were classified as abused and 288 (76.4%) were classified as non-abused. Abused subjects were more likely then non-abused subjects to be Less than 1 year of age (vs. >1 year of age) (OR: 9.8; 95% CI: 5.0, 19.2), covered by Medicaid (vs. commercial insurance) (OR: 2.8; 95% CI: 1.7, 4.8), and admitted to the ICU (OR: 3.5; 95% CI: 2.1, 5.8; p less than .001). The caretakers of abused subjects were more likely to give a history of no trauma or minor trauma compared to the caretakers of non-abused subjects (97% vs. 54%, p Less than .001). Length of stay was significantly greater for abused subjects versus non-abused subjects (mean: 9.25 days vs. 3.03 days, p < .001). Hospital charges (1999 dollars) were significantly higher for abused (mean ? SD: $40,082 ? $58,004) versus non-abused (mean ? SD: $15,671 ? $41,777) subjects. Conclusions: These results highlight the differences in the demographics, presenting characteristics and economic impact of abusive head injuries compared to non-abusive head injuries.